Bump tensorflow in /machine-learning/image-classifier

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 2.5.3 to 2.7.2.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v2.5.3...v2.7.2)

---
updated-dependencies:
- dependency-name: tensorflow
  dependency-type: direct:production
...

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Author: dependabot[bot]

machine-learning/image-classifier/requirements.txt

@@ -1,4 +1,4 @@
 matplotlib
 numpy
-tensorflow==2.5.3
+tensorflow==2.7.2
 tensorflow_datasets